Query parameters & clauses
When querying your data, you can use your query string to get the data, then sort and manage it on the client. This topic describes a few techniques.
API BaaS enables the fast retrieval of one of a large number of entities very quickly (random I/O). It does not perform well for retrieving an entire collection in excess of 1,000 entities.
On the backend API BaaS stores your data in a NoSQL (Cassandra) database. This makes your data store extremely flexible, but also requires a different approach to storing and retrieving data than users of a traditional RDBMS will be accustomed to.
Your query can search the text of entity values of the string data type. For example, you can search a postal code field for values that start with a specific three numbers.
For example, the following query selects all restaurants with the word
diner in the name:
/restaurants?ql=select * where restaurants contains 'diner'
Note: Not all string properties of the default entities are indexed for searching. This includes the
The following table lists a few examples of the kind of searches you can do in queries.
|Find books whose 'title' property contains the full word "tale".||
/books?ql=select * where title contains 'tale'
|Find books whose 'title' property contains a word that starts with "ta".||
/books?ql=select * where title contains 'ta*'
|Find books whose title property is exactly and only "A Tale of Two Cities".||
/books?ql=select * where title = 'A Tale of Two Cities'
If you've stored location data with your entities, you can query for the proximity of the geographical locations those entities represent. For more information on geolocation, see Geolocation.
|Find stores whose locations are within the specified longitude and latitude.||
/stores?ql=location within 500 of 40.042016, -86.900749
The return results are sorted in order of nearest to furthest. If there are multiple entries at the same location, they're returned in the order they were added to the database.
For more on geolocation queries, see Geolocation.
You can return query results that are sorted in the order you specify. Use the
order by clause to specify the property to sort by, along with the order in which results should be sorted. The syntax for the clause is as follows:
order by <property_name> asc | desc
The following table includes a few examples:
|Sort by first name in ascending order||
/users?ql=select * where lastname = 'Smith' order by firstname asc
|Sort by first name in descending order||
/users?ql=select * where lastname = 'Smith' order by firstname desc
|Sort by last name, then first name in ascending order||
/users?ql=select * where lastname contains 'Sm*' order by lastname asc, firstname asc
When your query might return more results than you want to display to the user at once, you can use the limit parameter with cursors or API methods to manage the display of results. By default, query results are limited to 10 at a time. You can adjust this by setting the limit parameter to a value you prefer.
For example, you might execute a query that could potentially return hundreds of results, but you want to display 20 of those at a time to users. To do this, your code sets the limit parameter to 20 when querying for data, then provides a way for the user to request more of the results when they're ready.
You would use the following parameters in your query:
Number of results to return. The maximum number of results is 1,000. Specifying a limit greater than 1,000 will result in a limit of 1,000.
You can also use the limit parameter on a request without a query string. The following example is shorthand for selecting all books and limiting by 100 at a time:
Using a limit on a DELETE can help you manage the amount of time it takes to delete data. For example you can delete all of the books, 1000 at a time, with the following:
Keep in mind that DELETE operations can take longer to execute. Yet even though the DELETE query call might time out (such as with a very large limit), the operation will continue on the server even if the client stops waiting for the result.
Select all users whose name starts with fred, and returns the first 50 results:
/users?ql=select * where name = 'fred*'&limit=50
||string||An encoded representation of the query position pointing to a set of results. To retrieve the next set of results, pass the cursor with your next call for most results.|
Retrieve the next batch of users whose name is "fred", passing the cursor received from the last request to specify where the next set of results should begin:
/users?ql=select * where name = 'fred*'&limit=50&cursor=LTIxNDg0NDUxNDpnR2tBQVFFQWdITUFDWFJ2YlM1emJXbDBhQUNBZFFBUUQyMVZneExfRWVLRlV3TG9Hc1doZXdDQWRRQVFIYVdjb0JwREVlS1VCd0xvR3NWT0JRQQ
Help or comments?
- If something's not working: Ask the Apigee Community or see Apigee Support.
- If something's wrong with the docs: Send Docs Feedback
(Incorrect? Unclear? Broken link? Typo?)